This invention is directed to overcoatings for sensors and processes for preparing these overcoated sensors.
In the above-mentioned patent applications there are described certain sensors and/or sensing systems for determining blood constituents. Typically of interest would be the determination of the concentration of gases (partial pressure of gases), such as oxygen and carbon dioxide, of hydrogen ions (pH), of other electrolytes, of glucose and the like in the blood. These provide useful parameters for assessment of certain physiological conditions of a patient.
The above-noted patent applications provide teachings for the construction of "sensors". These sensors are preferably of a sufficiently small size to be used directly in vivo in a patient. This contributes to monitoring the condition of the patient on a continuous basis, as opposed to older known procedures which required the extraction of a blood sample for determination in a laboratory of the constituents of interest in the blood.
Certain of the sensors of these patent applications utilize optical indicators, in particular fluorescence indicators, having an optical surface. Typically, a matrix material containing a fluorescent dye is loaded onto the optical surface of an optical fiber. Interaction of the dye with the component to be sensed is monitored utilizing optical signals carried by the optical fibers.
It would be advantageous to provide a durable sensor which has no substantial or significant detrimental effect of the patient being monitored.